As shown in FIG. 4, the conventional copy sorter is constituted such that: a copy sheet 51 ejected from the copying machine enters the space between an upper guide plate and a lower guide plate; then upper and lower rollers 50, 49 installed near a transfer wheel 58 and an auxiliary paper supplying unit installed separately are driven so that the copy sheet 51 is loaded upon a bin tray 39; and at the same time, the transfer wheel 58 is revolved to pick up pins 52 disposed at the opposite ends of the bin tray 39, so that the pins 52 should be moved in the vertical direction within a slot liner 53 having a vertically elongate shape such that the trays diverge to a certain gap, thereby forming a vertical linear slot liner type sorter (U.S. Pat. No. 4,466,608)
However, in such a type of sorter, only the up and down movements of the bin trays are possible, the stand-still position of the bin trays is located externally to the transfer wheel all the time, and a seperate paper supplying unit is required to overcome the separation between the bin tray and the ejecting section of the copying machine.
Another type of conventional sorter as disclosed in U.S. Pat. No. 4,589,653 is constituted such that a protuberance formed on a bin tray is picked up by means of a notch of a piped C-cam driven by a motor, so that the bin tray should be lifted or lowered. This type of sorter has the disadvantage of requiring a plurality of auxiliary units for lifting or lowering the bin tray.
Still another type of sorter as disclosed is U.S. Pat. No. 4,500,087 is constituted such that the lifting motion of the bin tray is generated by picking up a bottom pin by means of a wire winding method, while the lowering motion of the bin tray is generated by pushing the end of the bin tray by means of a solenoid connected to a pusher. In such a type of sorter, a slot liner of a vertical linear form is utilized, and therefore, only the up and down movements of the bin tray are possible, in addition to the fact that the driving means is complicated and inefficient.
Still another of sorter type as disclosed on U.S. Pat. No. 4,466,609 and 4,478,406 is constituted such that a spiral drum cam is utilized to generate up and down movements of the bin tray. This type includes the disadvantages that only simple up and down movements of the bin tray are possible, and a seperate conveyor unit is required for loading the copy sheets to the exact position on the bin tray.
U.S. Pat. No. 4,433,837 is constituted such that the middle portion of a slot liner is bent in an arcuate manner toward the tray, and a revolving ratchet picks up a pin, such that the pin is lifted by means of the end of the arcuate portion. Such an arrangement is for lifting the pin by means of the slot liner in a natural manner, and generates only simple up and down movements. Further, the distance between the bin tray and the ejecting roller of the copier is too large, and therefore, there is the disadvantage that the copy sheets discharged from the ejecting roller of the copying machine cannot be received at the exact position of the bin tray after natural drops from the ejecting roller.
U.S. Pat. No. 4,397,461 is constituted such that, without using a slot liner, the end portion of the bin tray is formed downwardly contrary to the preceding method, such that the bin tray is aligned in an unloaded state, thereby forming a free drop type. In the use of such a sorter, the action of taking out the copies from the tray becomes very unstable, and therefore, end users avoid the use of such products.
U.S. Pat. No. 4,343,463 is constituted such that a bin tray is installed on a vertically linear type slot liner such that the bin tray moves up and down owing to the function of a spiral drum cam. This sorter is designed such that it should be applicable only to the ejecting section of a copy machine of a special type, and therefore, it is accompanied by a limitation that it cannot be used for ordinary copy machines.
U.S. Pat. No. 4,328,963 and 4,432,377 are constituted such that a slot liner on which a bin tray is installed is bent toward the ejecting section of the copy machine, in such a manner that its middle portion has a vertical form. In this way, an effect almost the same as that of the preceding vertical slot liner types is achieved. That is, the bin tray is able to perform only up and down movements within the range of the transfer wheel, and therefore, as in the cases of the preceding types, a distance between the bin tray and the ejecting roller is formed, thereby making the loading of the copies unreliable.